Great team, with a great use of Scarf Tornadus-T, one of my favourite sets in this metagame. One problem I did see however was Sun Teams, and I was surprised these weren't included in your threat list. Offensive Sun Teams that carry Genesect plus a trapper look very problematic for you to face, as these types of team work by gaining momentum, and if Venusaur gets a free Growth up against Forretress, Politoed or even as Latias switches in, you have a big problem on your hands. From here, you pretty much need to get Politoed in and sac something else, only to revenge it again, which at this point can only be done by Tornadus-T. This is not a reliable way to deal with Venusaur, as you essentially have to let something die every time it switches in, and that doesn't cover what happens if you allow Venusaur or any other Chlorophyll abuser a free growth. There are a couple ways to deal with this, but the easiest imo would be to drop Refresh on Latias for Psyshock. Psyshock allows Latias to deal with Venusaur, as Dragon Pulse does not deal enough to Venusaur. This completely removes the free turn of setup Venusaur needs to actually do something against your team, meaning you do not have to let something die to revenge Venusaur. Additionally, Psyshock also allows you to deal with Choice Scarf Terrakion, something that you mentioned was a big threat to your team. Latias with Psyshock hits Terrakion much harder than Dragon Pulse does, while it also deters other variants of Terrakion such as Sub Swords Dance from setting up on Latias under Sand. Psyshock also means that you have something for Gengar, given that Gengar cannot OHKO your current Latias set, while Latias can easily dispose of Gengar with Psyshock. By losing Refresh, you lose the ability to beat status users such as Jellicent and Ferrothorn if it lacks Gyro Ball, but these are already dealt with by Lucario and Volcarona respectively, so I don't really see the need.
Also a little nitpick, I would recommend changing your Tornadus-T's set to 88 Atk / 252 SAtk / 168 Spe. With this set, you already outspeed everything that is relevant with a Scarf, including 180 Spe Timid Venusaur, Scarf Latios, Scarf Genesect, Scarf Terrakion, Adamant Stoutland and +2 bulky Volcarona. The extra EVs in attack actually add some power into your U-Turn, which is appreciated for the little bit of extra damage to put something into OHKO range for Lucario. As for Tornadus-T's moveset, I'd agree that Focus Blast would be a good option over Hidden Power [Ice] to help with Heatran, as Politoed and Lucario are your only options right now, and Heatran looks a little annoying for you to play against which is kind of ironic for a Rain Team. This also allows you to use Hidden Power [Ice] over Gyro Ball on Forretress to help with Dragons, while you should also use 52 SAtk EVs on Forretress if you use Hidden Power [Ice] to 2HKO Gliscor, Salamence and Landorus (T). The need for Gyro Ball is not as much as before if you decide to go with the Psyshock suggestion on Latias.